Overflow jack circuit



Dec. 15, 1931. E. P. BROE OVERFLOW JACK CIRCUIT Filed April 28, 1931 INVENTOR Ellfirae Wk ATTORNEY Patented Dec. 15, 1931 Enelmr. BROE, on NEW YORK, NIYZ, .AssIGNoR To mitnnrozuv TELEPHONE Ann Tam i GRAPH COMPANY, aeconroltarroni or NEWYORK r ovnarnow aa ciomoiiir Application filed April This invention relates to telephone systems and more particularly to improved signaling arrangements for such systems.

The primary object of the inventionis to provide arrangements whereby an'operator desiring to establish a connection a group of toll lines or trunks, all ofwhich are busy, may connect her cord circuitlto ajjack associated with the group of lines and re-:

ferred to as an overflow jack and may 'rleceive signalson her cord circuit supervisoryjilarnp which will at all times indicate'whether or not all circuits in the groupare busy. Affurth'e'r object of the invention consists in prov ding arrangements of the above type whereby 'a' plurality of operators desi'ringto establish;

connections with the group of linesmay con ne'ct their cord clrcu ts to multiples of the overflow jack and all receive these same's1gjnals. Further objects and features oi the invention will appear more fully 'from'the detailed description thereof hereinafter given.-

The invention may be more fully "undei stood from the following description together with the accompanying drawing inthefigure of which is shown a circuit diagram embodying a preferred form of the invention.

In the drawing is shown a group of out going lines L L L and Li which might be trunk, toll or other types of lines; These lines would terminate respectively jthe jacks J J J and J 4 and there wouldbe associated therewith the" signal lamps lL' L L and LC controlled by sleevetrelay's S S S and S These signal lamps are for indicating the idle condition of their respecr tive lines. Adapted to be associated with the group of trunk or toll lines is a cord circuit L equipped with a marginal supervisory relay CS and a lamp CL. Obviously the cord' mig'ht be another trunk or toll line if desired. Other cord circuits similarto L such for example as L' might alsobe provided. Associated with the group of toll lines would be a series of overflow jacks such as J O, J O, jetcZTfWith these overflow jacks would be associated sig na ling apparatus for accomplishingvtheiob lects of the invention. i

1531f seria No. "5, 33,555.

represents: by jacks J J J g and J are busyQth associated relays'.S ,-S2, 3 *ri will all be operated and the lamps I1 L,"

.L and LL will all'be extinguished; Relay C will; howeveflfb e operated, 1ts 'ci'rcuit bein traced from batt'ery 6l throughthe operated contactsof relays S 52, 8; and S andfth'e ation 1 of the yja'rrangements ill winding ofrelay'C to ground. Relay open a ted, connects battery tola'mp LO Which is associated Withf-ovrflow jack 0, causing therlamp to light, and also all other i tip s of this lamp such as LO'B Thercircuit for' lighting these lamps is fro'inbattery 62, nor? mal contact-of'relay L lead 10?,coritact13 A y 91 group "of outgping cir'cuits will upon per ceivin'g a lighted overflow lamp; realize" that desiring a connection to this allcirc'uits in the group are busy andwill then connect her cord to the overflow jack.

Assume" that one suchoperator connects' 'her lead 101, and through a parallel circuit consisting of winding l' of relay' A and Wind ing 2 ofreIay- B to ,"ground: Relays A and Bme bm: relaysian'd are so connected that eachwill operate-only on current t hrough its respective'winding 1 and then only if, a flowing through its' greater current is not I I Winding Upon completion of the above mentioned circuit relay Aoperatesr Sinceno current is as yet flowing through Winding- 1 of relay 13,1 it will not operate. 1 Relay A c one.

nects ground over lead' 103 toithe winding o'f'the steppingmagnet SM', thence over lea 105, contacts--12; 11;;andl'10'of ielayF to'bat tery 64', causing the magnet to advance the brushes, Bland B9) of switchfSWito the t er 7 contacts ONE As these contacts are part'of V vance of the brushes to contacts 21 and 31 serve no useful purpose at this time. The closure of contact 5, however,

connects ground to resistances RA and RB, thus completing circuits to allow current to flow in winding 2 of relay A and winding 1 of relay B. The value of resistance RA is such that stepping magnet SM is open andthe switch;

remains at rest with, its brushes upon terminals 21 and 31. i

Should one of theioutgoing circuits becoine'idle, for example,- the one connected to jack J 2, relay S2will release, causing lamp L2 to li ht and opening the circuit of relay G which will release. Relay C released, connects battery through its contact3 to relay F, thence through off-normal contact 4 and interrupter 6 to ground, causing relay to operate and release intermittently.- With relay'F released, relay CS inthecord is connected as described previously to relays A and B. This circuit is of low enough resistance to operate relay CSV lVith relayF operated, relay OS is connected over lead 102.to

resistance Hlwhich is of high enough resistance to cause relay CS to release. Relay CS thereforeoperates andlreleases in syn chronism with interrupter 6, causing lamp CL to'flash as. an indication'to the operator.

that acircuit is nowqavailable. Lamp L/2,,

now lighted, indicates the idle circuit; Relay F at its contacts 10, Hand 12 removesbattery, each time therelay operates from the stepping and release magnets SM and RM and from theoperating winding of relay B in order to prevent the switch from either advancing or restoring falsely.

' Assume,however, that before a circuit be came idle another operator desired connec tionto one of the circuits in this same group. Observing that lamp L0 is lighted, she

would connect her cord, such for example as cord L5, to jackQlO. Two relays similar to CSwill now be connected in parallel over leads 100 and 101 'tothe windings of relays A and B, resulting in an increase inthe cur rent flowing throughtheserelays. This increase inv current through winding 1 of relay A is ,suflicient to more than offset the, biasing current through winding 20f relay A,

and relay {A will, in consequence, operate.

I V "The increase in current through winding of relay will not I aifect this relayflsi nce winding 2 is the biasing winding whichis preventing relay B from operating.

With relay A operated again, the stepping magnet SM will again be energized, causing the switch to'advance its brushes to terminals 22 and 32. Brush B1 now completes a circuit to connect resistance L2'in parallel with the relays A and B. The value of resistan.ce.L2 is equal to the parallel resist-' .ance of'relays AandB. The circuit from thegsleeves of the jacks J0 and J0 to ground is, therefore, reduced to half its original valueso that normal current flows through the two relays CS causing both to operate and light the cord circuit supervisory lamps CL. The connection of resistance L-2 in parallel with relays A andB reduces the current through winding 1 of relay A so that the biasing. winding 2 will again cause the relay to release. The current through biasing winding 2 of relay B is also reduced but not enough to permit relay B to operate. If a circuit should become idle at this time, re-

lay F will again be caused to operate 'and'release intermittently and the sleeve lead will be transferred alternately from lead 101 to 102. The resistance to ground over lead 102 has alsobeen'reduced to one-halfits former value by the connection of resistance H2 inflparall'el with H1. This is .acco'me plilshed through brush B2 and switch termi na 32.

Theinsertion of a third cord in another multiple of jacks J O J 0' will in like manner increase the current through winding 1 of relay A causing it to operate and energize the stepping magnet of the switch. The. switch will advance its brushes to terminals 231ml v33, reducing the resistance of the two paths over leads 101 and 102 toonethird of the original value, and shunting relay. A so as to cause-its release. As shown in the drawing, provision is made for'the connection of four cords in parallel and the advance of the switchover four corresponding terminals. Sinceeach additional cord connected in parallel increases the current through relay'A by a smaller amount, the number of parallel connections which can be permitted is limited only by the sensitivity of relay A. For con venience the circuit as shown is limited to four such connections. It will be understood, however, that this is not a limitation in theinvention, but merelya matter of convenience.

Assumingthat a fourth cord isconnected in parallel with the three already described, relay:L4 will be energiized'after' the switch has advanced its brushes in the usual manner, and will remove battery from lead 107, thereby extinguishing the lamps LO, LO, etc.,as-asignal to the operators that no rm ther connections are to be made to these over flowjacks.-. i

The release of the switchvwill now be described. Whether one, two, three or four such parallel connections have been. established the position of the, switch will connect the ,proper L resistance in parallel with relays A and B so that both relays will be released. 1 I

. WVhen a circuit becomes idle and the operators are signaled by flashing of their cord circuit supervisory lamps, one or more such operators who may not be busy at the time will withdraw their plugs from the overflow jacks in order to establish connection to the idle circuit.

, The withdrawal of a plug from the jack will cause decrease in the current over lead 100, and in winding 1 of relay A and winding 2 of relay B. Relay A, already released, will not be affected by a reduction in current through its operating winding. Relay B, however, having the current reduced in its biasing winding 2, will now operate because of the greater current through its operating winding 1. Relay B, operated, will connect ground over lead 1-04 to release magnet RM, which will operate to==restore the switch to normal. Should relay F be operated at the moment when the cord is withdrawn, the operation of relay B and release magnet RM will not occur until relay F has released since the battery circuit for relay 13 over lead 106 is open at contact 11 of relay F, and that for the release magnet is open at contact 12.

. lVith, the release magnet operated, the switch will restore its brushes to normal, and will open its oil-normal contacts 4- and 5. Contact 5 open, interrupts the operating circuit of relay-B which will release. .1 any cords remainconnected to the jacks J0, J0. etc, relay A will immediately be energized since its biasing Winding 2 has been: opener. at oft-normal contact 5. Relay A, operated, will again close the circuit for stepping magnet SM, causing it to be energized and to ad vancethe switch brushes to a point at which the shunt provided by the L resistance ,(L2, L73 or 1/4) reduces the current through winding 1 of relay A sufficiently to cause relay A to release, and prevent the further advance of the switch. j

Although no use is made of'the tip and ringconductors in the foregoing description,

it willbe understood that the si nals can be as easily transmitted over these conductors as the sleeve, the supervisory relay in the cord being suitably connected to receive them.

While the invention has been disclosed as embodied in certain specific arrangements which are deemed desirable, it is understood that it is capable of embodiment in many and other widely difierent forms without de parting from thespirit of the invention as cuits adapted to be connected to said lines and each including in its sleeve clrcurt mar inal si malim means a aluralit Y of over g D b flow jacks Ihaving a relay common thereto and operated whenall of said telephone lines arc'busy, a sleeve circuitcommon to all or" said overflow JacKs, a polar relay having an operating .winding'connected to said common sleeve circuit and operated when a link circuit is connected to one of-said overflow jacks,

and means controlled by said polar relay for operating the marginal-signaling means of the link circuit connected to the overflow jack. I i

2. A telephone system comprising a plurality of telephone lines terminating in jacks and signaling means, a plurality of link circuits adapted to be connected to said lines and each including in its sleeve circuit marginal signaling means, a plurality of overflow jacks having a relay common thereto and operated when all of said telephone lines are busy, a sleeve circuit common to all 0t said overflow jacks, a polar relay having an operating winding connected to said common and signaling means, a plurality of link cir- V cuits adapted to be connected to said lines and each includingin its sleeve circuit marginal signaling means, a plurality of overflow jacks having a relay common'thereto and operated when all of said telephone linesare busy, a sleeve circuit common to all ofsaid overflow jacks, a polar relay having its operating winding connected to said common sleeve circuit and operated when a link circuit is-connected to one of said overflow jacks, and means controlled by said polar relay and said relay. common to said overflow jacks for intermittentlyoperating the marginal relay means of the link-circuit connected to the overflow-jack. i

4. Atelephone system comprising a plurality of telephone lines terminating in 3acks and signaling 'means,-a plurality of link cir' cuits adapted to be connected to said lines and each including in its sleeve circuit marginal signaling means, a plurality of overflow acks having a relay common thereto and operated when all of said telephone lines arebusy, a sleeve circuit common to all of said overflow -j acks, a polar relay having its operating winding conneetedto saidcommonsleeve circuit and operated whenever said link circuits are connected to said overflowjacks, and

means controlled by said polar relay and said relay commonto said overflow jacks for inter- I inittently operating the marginal signaling f and each including in its sl eve circuit marginal signaling means, a plurality of overflow jacks having a relay common thereto and operated when all ol' said telephone lines are busy, a sleeve vcircuit common to all of said overflow' jacks, a polar relay having its operating winding connected to said common sleeve circuit and operated whenever link circuit is'connec'ted to onset said overflow jacks, and means controlled by said polar relay and the relay common to said overflow jacks for intermittently varying the resistance of said common sleeve circuit whereby the marginal signaling means in said connected link circuit may be operated intermittently.

A telephone system comprising a plurality of telephone linesterminating in jacks and signaling means, a plurali y of link circuits adapted'to be connected to said lines and each including in its sleeve circuit marginal ignaling means, a plurality of overflow "flZS having a relay'coinmon thereto and optted when all oi 'said telephone lines are busy, a sleeve circuit common to all of said overflow jacks, a polar relay having its op erating winding connected to said common ve circuit and operated when ever a link circuit is connected to one of said overflow jacks, a stepping magnet operated by said polar relay'and means controlled by the operation of said stepping magnet for releasing said polar relay and for intermittently applying ground to a circuit for varying the resistance of said coinmon'sleeve circuit whereby the marginal signaling means in said connected link circuit may be operated intermittently, said circuit to which ground is intern'iittently applied being controlled by said relay common to said overflow acks. I i

7. A telephone system comprising aplurality oftelephone lines terminating in acks and signaling means, a plurality'of link circuits adapted to be connectecL to said lines and each including in its sleeve circuit marginal signaling means, a plurality of overflow iacks having a relay common thereto and operated when all of said telephone lines are busy, a

sleeve circuit common to all of saidoverfiow mittent variation of the resistance of said common sleeve circuit whereby the marginal signaling means in said connected sleeve circuit may be intermittently operated, and additional six itching means controlled by said circuit is connected to one of -said overflow jacks. r I v I 8. A telephone system comprising a plurality of telephone linesterminating inj'acks and signaling means, a plurality of link circuits adapted to be connected to said jacks and each including in its sleeve circuit a marginal signaling means-and sourceof current, a plurality of overflow jacksfhaving a relay common thereto and operated when all of said telephone lines are busy, a sleeve circuit common to said overflow jacks, a polar relay having its operating. winding connected in parallel with said common sleeve circuit and operated when a link circuit is connected to one of said overflow jacks, switching means controlled by the operation of said polar relay for decreasing the resistance connected to said common sleeve circuit in parallel with the operating winding of said polar relay, and additional switching means controlled by said polar relay for operating said marginal signaling means in said link circuit.

9. A telephone system comprising a plurality of telephone lines terminating in jacks and signaling means, a plurality of link circuits adapted to be connected to said jacks and each including in its sleeve circuit a marginal signaling means and a source of current, a plurality of overflow jacks having a relay common thereto and operated when all of said telephone lines are busy, a sleeve circuit "common to said overflow jacks, a polar relay having anoperating circuit connected in parallelwith said common sleeve circuit and efi'ective when a link circuit is connected to one of said overflow jacks and a releasing circuiteflective when said relayis operated, switching means controlled by the operation of said polar relay for decreasing the resistance connected to said common sleeve circuit in parallel with the operating circuit of said polar relay whereby when a second link circuit is connected to one of said overflow acks the current through the operating circuit of said polar relay will be restored to normal value and the releasing circuit will remain effective, and additional switching means controlled by said polar relay for operating said marginal signaling means in said connected link circuits.

-10. "A'telephone system comprising a plurality of telephone lines terminating in jacks and signalin means, a plurality of jacks, a polar relay having an operating circuit connected in parallel with said common sleeve circuit and effectlve when a link c1rcuit 18 connected to one of sald overflow jacks and a releasing circuit effective when said relay is first operated, switching means controlled by the operation ofsaid polar relay for decreasing the resistance connected to said common sleeve circuit in parallel with the operating circuit of said polar.relay whereby when an additional link circuit is connected to one of said overflow jacks the current through the operating circuit of said polar relay will be restored to a normal value such as when only a single link circuit is connectedto the overflow jacks and whereby the releasing circuit will remain effective, a second polar relay having a releasing circuit connected in parallel with said common sleeve circuit and an operating circuit completed by the operation of said first polar relay but not eflective when the current flow over said common sleeve circuit and through the releasing winding of said second polar relay is equal to or greater than said normal value, additional switching means controlled by said first polar relay for operating said marginal signaling means in said connected link circuits, and means controlled by said second polar relay for restoring said switching apparatus to normal.

going lines and a plurality of associated overflow jacks, signals for said overflow jacks, means for automatically actuating the signals of said overflow jacks in response to seizure of all of the lines of the group, operators link circuits adapted to be connected to said overflow jacks when all of said lines are busy, signal devices associated with each of said link circuits and meansthereafter responsive to the release of any one of the lines to operate the signal devices of said link circuits. r c 7 12. In a telephone system, a group of outgoing telephone lines, overflowjacks asso ciated with said group of lines, link circuits adapted for connect-ion to said group of lines or to said overflow jacks, signaling means associated with each'of said link circuits, signaling means associated with each of said overflow jacks to indicate the busy condition of said group of lines, and means associated with said group of lines and said overflow jacks for operating in a distinctive manner the signals means in anyof said link circuits connected to said overflow jacks when 11. In a telephone system, a group of outall of the'lines of said-group are busy and for-operating said signaling means in 'a dif= ferent manner when one of. the line'sof said; group becomes idle. I '1 13. In a telephonesystem, a group ofoutgoing 'telephone lines, overflow. jacks associ'ate d with saidgroup of lines,-link circuits adapted for connection to said groupofllines or to'said overflow iacks,-signaling means associated with each of said link circuits,

signaling means associated with each of said of said group of lines, means associated with said group of linesand said overflow jacks for operating in a distinctive manner the signal means in any of said link circuits connected to saidoverflow jacks when all of the lines of said group are busyand for operating said signaling means in a different manner when one of the lines of said group becomes idle, and additional. means associated with said overflow jacks for releasing the signaling means associated with each of said overflow jacks when a predetermined number of said link circuits are connected to said overflow jacks.

overflow jacks to indicate the busy condition 7 associated with said group of lines and L adapted to receive the connection of a plurality of said link circuits, means associated v with said overflow jacks and said group of lines wherebyall of said connected link circuits will receive the same signals when said group of lines are busy and whereby all will receive another signal when one of said group of lines becomes idle, and means whereby the number of said link circuits which maybe connected to said overflow jackswill'be limited to a predetermined number. p

15. In a telephone system, a group ofoutgoing telephone lines, overflow jacks. assoi ciated with said group of lines, link circuits adapted for connection to said group I IO' of lines or to said overflow jacks, marginal signaling means in each of said link circuits, an operating'circuit for sald margmal 81g.- naling means completed over the sleeve contacts of said overflow jacks, and means associated with sald'overflow acks for reducmg the resistance 1n said operatlng circuit for said marginal relays in proportion to the number of said link circuits connected to said overflow jacks. I

16. In a telephone system, a vgroupof outgoing telephone lines, overflow 'jacks asso ciated with said group of lines, link circuits adapted for connection to said group of lines or to said overflow acks, signaling means in said link circuits, means responsive to the con-c nectlon of a lmk c1rcu1t to one of said overflow jacks and again responsive to the connection of a second link circuit to another of said overflow jacks for operating the signalingr means in 'said -connected. ,li'nk; Circuits; and means responsive to the" disonnection (ifany of'said'lin'k circuits. fromgsaid-bverflow jacks for restoring the mechanisml to normal condition. 1;; 7 In, testimony whereof, v I hwel signed #my' name to this specification this 27th ,dayiof 2 EDGAR-ERROR; 

